[A late phase II study of CPT-11 (irinotecan) in advanced breast cancer. CPT-11 Study Group on Breast Cancer]

A late phase II study of CPT-11 for advanced breast cancer was conducted at 27 institutions. Seventy-nine patients were enrolled, 75 were eligible for the study, and 65 were evaluable for efficacy. One complete response and 14 partial responses were obtained, and the response rate was 23%. The response rate of patients with prior endocrine therapy and prior chemotherapy including adriamycin or other anthracycline drugs was 27% (11/41) and 26% (12/46), respectively. The response rate for patients with estrogen receptor-negative tumors and premenopausal patients was 32% (6/19) and 27% (4/15), respectively. Responses were observed not only for soft tissue lesions such as lymph nodes (5/17), but also for distant metastases in the lungs (8/28) and bone (1/18). The major adverse reactions were myelosuppression and gastrointestinal symptoms. The incidence of Grade 2 or higher leukopenia, anemia, nausea/vomiting, anorexia, diarrhea and alopecia was 68%, 31%, 67%, 59%, 37%, and 30%, respectively. These results suggested that CPT-11 was a promising drug for advanced breast cancer.